From: Dave Kleikamp Subject: Re: [RFC PATCH v2 18/21] ext4: add support for read_iter and write_iter Date: Mon, 02 Apr 2012 19:11:28 -0500 Message-ID: <4F7A4030.5020701@oracle.com> References: <1333122228-13633-1-git-send-email-dave.kleikamp@oracle.com> <1333122228-13633-19-git-send-email-dave.kleikamp@oracle.com> <20120402184204.GE2880@thunk.org> <4F7A2BFE.8000609@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: "Ted Ts'o" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Zach Brown , Andreas Dilger , linux-ext4@vger.kernel.org Return-path: Received: from acsinet15.oracle.com ([141.146.126.227]:20085 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751295Ab2DCALh (ORCPT ); Mon, 2 Apr 2012 20:11:37 -0400 In-Reply-To: <4F7A2BFE.8000609@oracle.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 04/02/2012 05:45 PM, Dave Kleikamp wrote: > On 04/02/2012 01:42 PM, Ted Ts'o wrote: >> On Fri, Mar 30, 2012 at 10:43:45AM -0500, Dave Kleikamp wrote: >>> use the generic .read_iter and .write_iter functions >> >> Potentially silly question --- why not use NULL pointer to mean >> generic_file_read_iter and generic_file_write_iter? Then you won't >> have to patch a bunch of file systems to add the generic .read_iter >> and .write_iter? > > I'm not very confident that generic_file_read_iter and > generic_file_write_iter will work for every filesystem that I haven't > yet touched. It should work if they use generic_aio_read and _write, but > some have their own versions of those. In fact, I just realized a big oversight on my part in that I have ext4 calling generic_file_write_iter(), when in fact, it should be doing the equivalent of ext4_file_write(). If been chasing a bug assuming that ext4 called generic_aio_write(). Sometimes I miss the obvious. > > Shaggy